There's some useful information in this article:
www.diarrheadietitian.com/?p=455Looking at the chart in the article Gatorade doesn't seem to have the right ratio of sodium to potassium to be effective for severe dehydration. The article states that the higher the osmolality (see chart) the higher the risk of osmotic diarrhea. Gatorade has a relatively high osmolality so it does seem that it can make diarrhea worse.